Stop for the carriages of screw-cutting lathes



(No Model.)

T. HESLIN.

STOP FOR THE. OARRIAGES 0F SCREW CUTTING LATHES. No. 387,514. Patented Aug. 7, 1888.

f/Zm 75 BY AA 12% M ATTORNEYS.

N. PETERS. Phatofilhogr-qahcr. Wn-hingmu. n. c.

Fries.

THOMAS HESLIN, OF \VATEBTOWVN, NFHV YORK.

STOP FOR THE CARRIAGES OF SCREW-CUTTlNG LATHES.

SPECIFICATION forming part of Letters Patent No. 387,514, dated August 7, 1888.

Application filed April 26, 1888.

T0 aZZ whom it may concern.-

Be it known that I, THOMAS HESLIN, of lVatertown, in the county of Jefferson, in the State of New York, have invented new and useful Improvements in Serew-Gutting-Lathe Attachments, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

In ordinary screw-cutting lathes the toolcarriage is returned from the end of the cut to the beginning of the cut by the reverse motion of the lead-screw, and thus the tool is maintained in its requisite position in relation to the screw to be cut so as to follow the same successively. This entails the employment of two driving-belts running in opposite directions and shifters for throwing from loose pulleys to fastened pulleys, and also causes a considerable loss of time. To obviate these defects several devices have been resorted to for throwing the tool-carriage out of gear with the leadscrew at the end of the cut of the tool and returning the carriage to the starting-point by hand; but these devices required either a gage or graduated scale adj nstably connected to the lathe-bed, or an indicator operated by the leadscrew, so as to indicate the relative position of the tool-carriage and lead-screw, and the manipulation of said devices required a skilled mechanic. Besides this, the adjustment of the tool-carriage to its starting-point caused considerable loss of time, and the devices were expensive and liable to rapid wear.

The object of my invention is to obviate all of said defects; and to that end it consists of a simple inexpensive abutment or stop which is applicable to any ordinary screw-cutting lathe, and is readily secured in proper position to arrest the return movement of the tool-carriage at the starting-point of the serew-threads to be cut, and requires no adjustment and no skilled labor, and is positive and reliable in its operation.

In the annexed drawings, Figure 1 is a perspective view of that portion of the lathe-bed to which my invention is applied, and Fig. 2 is a detached perspective view of the stop.

L represents the Iathebed, formed with the usuallongitudinal guide-rib, a, on top and with the horizontal flange c.

D denotes the tool-carriage, which rides on the aforesaid bed, and is guided by the rib a Serial No. 271,962. (No model.)

entering a groove, h, in the under side of the carriage,in the usual manner, the tool-carriage receiving motion from the rotating feed-screw by a two-part nut connected to the carriage, and adapted to be thrown in and out of gear with the feed-screw in the well-known man ner. (Not necessary to be here illustrated.)

0 represents the stop by which to arrest the return movement of the carriage at the starting-point of the screw-threads to be cut. This stop is applied directly to the lathe-bed, and lies across the rib a, with which it engages by a groove, 0, in the under side of the stop. Said stop is also formed with a pendent yoke, I), which reaches under the flange e of the lathebed, and by a set-screw, (1, working vertically through the horizontal inward-proj eeting portion of the yoke and engaging the under side of the flange c, the stop 0 is firmly clamped on the lathe.

In the operation of euttingscrew-thrcads on the article held between the live-spindle and dead-spindle of the lathe the tool-carriage D is set in position to bring the tool to the point where the screw-threads are to begin on the aforesaid article. Then the stop 0 is set in a position to abut against the side of the carriage from which the latter is to move in cut ting the screw-threads, and in this position the aforesaid stop is to be securely clamped by tightening the set-screw d. When this is cffeeted, the stop is in position to perform its function, and no further adjustment or other manipulation of the stop is required thereafter until another article requiring a different length of screw-threads is put in the lathe. As soon as the stop is fastened on the lathe the latter can be set in motion, and when the tool carriage D arrives at the poi nt where the screw threads are to terminate, the attendant of the lathe throws the two-part nut of the carriage out of gear with the lead-screw and moves the carriage back to the stop 0 by hand, and as soon as the carriage strikes the stop the attendant throws the two-part nut again into gear with the lead-screw, which moves the toolcarriage forward to cause the tool to deepen the preceding cut.

It will be observed that by my improvement the use of scales or indicators is dispensed with and the time and care required to properly ad- ,j ust by said scale or indicator the tool-carriage in relation to the lead-screw at the beginning of the screw-threads to be out are saved.

My invention must not be confounded with the numerous devices employed for automati- 5 cally throwing oil the feed on screw-eutting lathes, and thereby stopping the action of the cutting-tool at any given position on the work. A practical machinist will readily com prehcnd the difference of my invention from such prior ID devices, and will also readily appreciate the merits of my invention.

My invention is not designed to entirely re lieve the attendant of the lathe from attention to the work. He is required to throw the feed 15 out of gear 'byhand and slidethe tool-carriage back to its starting-point.

The object of my invention is to relieve the attendant of the lathe from the care of finding the said starting-point and to insure the pre- 20 cise following of each successive cut of the the tool'carriagc after the latter has been set back a sullicient distance from the point where the screw-cutting is to commence, and in doing this the machinist need not take particular care in setting the tool-carriage to any particular point.

Having described my inventioinwhat I claim as new, and desire to secure by Letters Patent, 13-- On a screwcutting lathe, the combination, with the lathebed, ofa stop clamped rigidly thereon at a point to abut against that side of the tool-carriage from which the latter is to move in cutting the scrcwthreads, substantially as described and shown.

In testimony whereof I have hereunto signed my name, in the presence of two witnesses, at \"atertown, in the county of J cil'erson, in the State oi'Ncw York, this 28d day of April, 1888.

THOMAS nnsLrN. 11. s]

Witnesses:

Geo. W. H u :1: av, 11. A. FIELD. 

